Rodent Surveillance

District laboratory staff conducted a rodent survey for hantavirus with California Department of Public Health (CDPH) staff on June 4-5 in La Honda. Peromyscus truei (pinyon mice) and Peromyscus californicus (parasitic mice) were trapped and blood samples were taken for testing. Kidney samples from any mice with positive blood samples will also be tested by the CDPH to be used for a study of the geographical distribution of different hantavirus strains in California.

The laboratory began yearly surveillance for hantavirus with a rodent survey at San Bruno Mountain on May 2-3. Peromyscus maniculatus (deer mice) were trapped and blood samples were taken for testing. The mouse carcasses will be tested by the California Department of Public Health (CDPH) and positive samples will be used for a study of the geographical distribution of different hantavirus strains in California.

Laboratory staff conducted three surveys of wild rodents in the months of July and August. The surveys took place in Montara on July 17th and 18th, at Water Dog Lake park in Belmont on August 15th and 16th and Eaton and Big Canyon parks in San Carlos on August 29th and 30th. Blood samples were taken from captured rodents by a subocular bleed with a microcapillary tube and ear punches were also taken from the rodents at Water Dog Lake, Eaton and Big Canyon parks.

Laboratory staff conducted two surveys of wild rodents in the month of June. The surveys took place in Water Dog Lake park in Belmont on June 14th and 15th and Eaton and Big Canyon parks in San Carlos on June 20th and 21st. Blood samples were taken from captured rodents by a subocular bleed with a microcapillary tube and ear punches were also taken from the rodents. The blood and ear tissue will be tested in our District laboratory for Borrelia bacteria that cause Lyme disease and other infection.

The District conducted two wild rodent disease surveys on San Bruno Mountain this year, and all test results have been received. Each survey consisted of 100 Sherman traps placed along trails, targeting wild mice. The first survey resulted in fifteen captured Peromyscus maniculatus mice and the second survey resulted in eleven captured P. maniculatus mice.

During May, District staff, in conjunction with the California Department of Public Health, trapped and tested rodents for Sin Nombre hantavirus in areas of Montara, CA. Each rodent was anesthetized, then measured and checked for parasites. Laboratory staff then drew blood for the hantavirus antibody test. After recovering from anesthesia, each rodent was carefully released at the exact location where it was trapped. Staff tested a total of 13 mice.

On March 28th and 29th, District staff, in conjunction with the California Department of Public Health, trapped and tested rodents for Sin Nombre hantavirus at San Bruno Mountain State & County Park. Each rodent was anesthetized, then measured and checked for parasites. Laboratory staff then drew blood for the hantavirus antibody test. After recovering from anesthesia, each rodent was carefully released at the exact location where it was trapped. Staff tested a total of 15 mice.

On November 14th, District staff, in conjunction with the California Department of Public Health, trapped and tested rodents for Sin Nombre hantavirus at San Pedro Valley County Park. Staff set 100 traps and caught twenty six rodents in them. Each rodent was anesthetized, then measured and checked for parasites. Laboratory staff then drew blood for the hantavirus antibody test. After recovering from anesthesia, each rodent was carefully released at the exact location where it was trapped. Staff tested a total of twenty four mice. Test results showed that